Much has been made about who the subject of Katy Perry's latest hit, "Part of Me," might be. Is it her ex-husband, Russell Brand, or, given that she wrote it a while back, her other famous ex, Gym Class Heroes frontman Travie McCoy?

Does it even matter? The song is an emotional breakup anthem that just about anyone can relate to; set to a 130-beat-per-minute house beat, it's sure to have club kids the world over dancing their faces off.

With the military-themed video for "Part of Me" premiering as part of "MTV First: Katy Perry" on Wednesday (March 21) at 7:23 p.m. ET on MTV, we decided to take an in-depth look at the song to let you know what it's all about.

"Part of Me" was written two years ago during Perry's sessions for Teenage Dream. Perry co-wrote the song with Bonnie McKee and the writing/production team behind Dream's biggest hits, Dr. Luke and Max Martin ("Teenage Dream," "Last Friday Night," "The One That Got Away").

While she reportedly did rework the lyrics after a demo of the track leaked online, Perry told MTV News recently that the kiss-off track is not directly about her relationship with Brand. "Some people that I work with were like, 'You should just say you wrote it a couple of weeks ago.' I'm like, 'I'm not a d---, I'm going to tell the truth,' " she said. "I wrote it two years ago when I was writing and recording Teenage Dream, [but] it didn't feel right on the record. I'd have to take out one of my other songs that [made the album] a nice, complete package."

On the track, Perry declares herself unbreakable after a breakup, singing, "Days like this I want to drive away/ Pack my bags and watch your shadow fade/ 'Cause you chewed me up and spit me out/ Like I was poison in your mouth/ You took my light, you drained me down/ But that was then and this is now."

The plan, according to Perry, had always been to release the song as part of a deluxe edition of her record-breaking album. "I always planned to put it out in the spring of this year, to possibly perform it at a big thing," Perry told MTV News.

And that's exactly what she's done. The track is included on Teenage Dream: The Complete Confection, out March 26, and Perry debuted "Part of Me" in February during her performance at the 54th Grammy Awards. She segued from her spacey "E.T." into the new dance-pop track while rocking the stage at Los Angeles' Staples Center wearing a body-hugging silver and gold bodysuit.

The performance was her first since announcing her divorce from Brand, and because the lyrics so directly deal with moving on after a failed relationship, speculation ran rampant that the song was her kiss-off to Brand. While that's definitely not the case, Perry admits the parallel between the lyrical content and what is going on in her own life is "serendipitous."

"I sit down and I write all these songs at once, all these emotions and feelings and thoughts, and then, like, it just feels like sometimes I'm caught in this movie where my life is paralleling my music," Perry told MTV News. "It seems very serendipitous, but for me, as un-fun as it sounds, I prepare everything. I'm overly prepared and kind of a control freak in the best of ways."

Still, all that planning has paid off in spades. "Part of Me" debuted at #1 on the Billboard Hot 100 in late February after selling a staggering 448,000 downloads in its debut frame, the most of any song since Lady Gaga's "Born This Way" dropped almost exactly a year earlier.

Following the on-air premiere of "Part of Me," visit MTV.com, where MTV News' James Montgomery will chat with Perry about the video, Teenage Dream: The Complete Confection and her upcoming concert movie, "Katy Perry: Part of Me."

Catch "MTV First: Katy Perry" on Wednesday, March 21, when the pop star will debut her long-awaited video for "Part of Me" at 7:23 p.m. ET on MTV. Then head over to MTV.com for an exclusive 30-minute interview with Perry!